In the production of nylon pile fibers, it is often desirable to emboss the surface thereof in order to provide extra decorative appeal. Im some instances, the embossed areas are printed with dyes to embellish the surface design and to develop multi-colored embossed patterns.
Embossing of pile fabrics is conventionally accomplished with a heat embossing roll or plate which has been engraved or otherwise treated to create the design desired in raised relief on the surface. A method which eliminates the use of embossing rolls has been disclosed in U.S. Pat. Nos. 2,790,255 and 2,875,504. In accordance with these patents, pile fabric is formed from a combination of (shrinkable and non-shrinkable) yarns. Upon subjecting the fabric to the influence of heat, the pile formed from the shrinkable yarns contracts while the base and the non-shrinkable yarns remain intact thereby yielding a pile made up of high and low areas to give the appearance of an embossed or carved product.
A chemical embossing method is disclosed in U.S. Pat. No. 2,020,698. According to this patent, fabric having a pile of organic ester or cellulose yarn is locally treated with an alkali or alkaline salt saponifying agent in order to obtain ornamental differential effects in the treated areas. Furthermore, since the organic ester of cellulose pile yarns that have not been saponified are more difficult to change from their position, after they are once set than are the saponified organic ester of cellulose yarns, it is possible to obtain a differential lay between the saponified and unsaponified organic ester of cellulose pile yarn. Thus, the fabric, after the application of the saponifying agent, may be washed, finished and dried with the pile erect, after which the fabric may be run through water and brushed across the piece to lay the pile towards the selvage and it is then dried. This causes the saponified pile yarn to lie flat while the unsaponified yarn remains substantially erect. Upon subsequent steaming and brushing the fabric in the opposite direction, any unsaponified yarn which may have been slightly bent from the vertical by the previous brushing toward the selvage is caused to stand erect without disturbing the position of the laid or crushed saponified organic ester of cellulose pile yarn.